On 19/08/2019 23:34, Jordan Crouse wrote:
On Mon, Aug 19, 2019 at 07:19:31PM +0100, Robin Murphy wrote:
Now that callers are free to use a given table for TTBR1 if they wish
(all they need do is shift the provided attributes when constructing
their final TCR value), the only remaining impediment is the address
validation on map/unmap. The fact that the LPAE address space split is
symmetric makes this easy to accommodate - by simplifying the current
range checks into explicit tests that address bits above IAS are all
zero, it then follows straightforwardly to add the inverse test to
allow the all-ones case as well.
Signed-off-by: Robin Murphy <[email protected]>
---
drivers/iommu/io-pgtable-arm.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c
index 09cb20671fbb..f39c50356351 100644
--- a/drivers/iommu/io-pgtable-arm.c
+++ b/drivers/iommu/io-pgtable-arm.c
@@ -475,13 +475,13 @@ static int arm_lpae_map(struct io_pgtable_ops *ops,
unsigned long iova,
arm_lpae_iopte *ptep = data->pgd;
int ret, lvl = ARM_LPAE_START_LVL(data);
arm_lpae_iopte prot;
+ long iaext = (long)iova >> data->iop.cfg.ias;
/* If no access, then nothing to do */
if (!(iommu_prot & (IOMMU_READ | IOMMU_WRITE)))
return 0;
- if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias) ||
- paddr >= (1ULL << data->iop.cfg.oas)))
+ if (WARN_ON((iaext && ~iaext) || paddr >> data->iop.cfg.oas))
return -ERANGE;
prot = arm_lpae_prot_to_pte(data, iommu_prot);
We'll want to cast away the sign extended bits before mapping the iova, this
might be a good patch for that too as long as we are calculating the iaext.
Ah good point, I'd forgotten that ARM_LPAE_LVL_IDX() doesn't actually
cap to IAS if the top level is smaller than bits_per_level (I suppose we
*could* make it do so for purity, but that's bound to hurt efficiency
far more than just zeroing out the offending bits here).
Thanks,
Robin.
@@ -647,8 +647,9 @@ static size_t arm_lpae_unmap(struct io_pgtable_ops *ops,
unsigned long iova,
struct arm_lpae_io_pgtable *data = io_pgtable_ops_to_data(ops);
arm_lpae_iopte *ptep = data->pgd;
int lvl = ARM_LPAE_START_LVL(data);
+ long iaext = (long)iova >> data->iop.cfg.ias;
- if (WARN_ON(iova >= (1ULL << data->iop.cfg.ias)))
+ if (WARN_ON(iaext && ~iaext))
return 0;
return __arm_lpae_unmap(data, iova, size, lvl, ptep);
And here too.
Jordan
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